Financial Instruments

12 Months Ended

Mar. 31, 2018

Financial Instruments [Abstract]

Financial Instruments

(3)  FINANCIAL INSTRUMENTS

Cash and Cash Equivalents

As of March 31, 2018 and 2017, our cash and cash equivalents were $4,258 million and $2,565 million, respectively. Cash equivalents were valued using quoted market prices or other readily available market information.

Short-Term Investments

Short-term investments consisted of the following as of March 31, 2018 and 2017 (in millions):

	As of March 31, 2018									As of March 31, 2017
	Cost or Amortized Cost		Gross Unrealized					Fair Value		Cost or Amortized Cost		Gross Unrealized					Fair Value
			Gains		Losses							Gains		Losses
Corporate bonds	$	629	$	—	$	(5	)	$	624	$	944	$	—	$	(1	)	$	943
U.S. Treasury securities	212		—		(2		)	210		414		—		(1		)	413
U.S. agency securities	79		—		(1		)	78		152		—		(1		)	151
Commercial paper	109		—		—			109		212		—		—			212
Foreign government securities	53		—		(1		)	52		113		—		—			113
Asset-backed securities	—		—		—			—		135		—		—			135
Short-term investments	$	1,082	$	—	$	(9	)	$	1,073	$	1,970	$	—	$	(3	)	$	1,967

The following table summarizes the amortized cost and fair value of our short-term investments, classified by stated maturity as of March 31, 2018 and 2017 (in millions):

	As of March 31, 2018				As of March 31, 2017
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Short-term investments
Due within 1 year	$	521	$	520	$	1,237	$	1,236
Due 1 year through 5 years	561		553		721		719
Due after 5 years	—		—		12		12
Short-term investments	$	1,082	$	1,073	$	1,970	$	1,967